Okay folks, this DIY is in conjunction with the AC Compressor writeup
that I did. If you had to replace your compressor, then you should also replace the accumulator and orifice as all three devices are critical to your AC's effective operation. This writeup is assuming that you have not had a catastrophic failure, which would constitute you having to flush the entire system. Flushing is NOT necessary if your system failure was not catastrophic. I am going to keep this as close to the GM service manual as possible. Here we go!
Step 1. Recover the refrigerant from the A/C system.
Now if you are an average Joe like me, you probably don't have one of these machines just sitting around in a corner somewhere so you will have to visit a place that does. If your compressor has discharged all the R-134a in your system, you still do not want to just start breaking loose the lines as some R-134a will remain and this stuff is DANGEROUS. You do not want to be breathing this stuff. It is heavier than air so do not be laying up under the car if that is were you decide to break the first line. Make sure that you work in a well ventilated area when you do break that first line.
Here are the cations and notices from the service manual:
Avoid breathing the A/C Refrigerant 134a (R-134a) and the lubricant vapor or the mist. Exposure may irritate the eyes, nose, and throat. Work in a well ventilated area. In order to remove R-134a from the A/C system, use service equipment that is certified to meet the requirements of SAE J 2210 (R-134a recycling equipment). If an accidental system discharge occurs, ventilate the work area before continuing service. Additional health and safety information may be obtained from the refrigerant and lubricant manufacturers.
For personal protection, goggles and gloves should be worn and a clean cloth wrapped around fittings, valves, and connections when doing work that includes opening the refrigerant system. If R-134a comes in contact with any part of the body severe frostbite and personal injury can result. The exposed area should be flushed immediately with cold water and prompt medical help should be obtained.
R-134a is the only approved refrigerant for use in this vehicle. The use of any other refrigerant may result in poor system performance or component failure.
To avoid system damage use only R-134a dedicated tools when servicing the A/C system.
Use only Polyalkylene Glycol Synthetic Refrigerant Oil (PAG) for internal circulation through the R-134a A/C system and only 525 viscosity mineral oil on fitting threads and O-rings. If lubricants other than those specified are used, compressor failure and/or fitting seizure may result.
R-12 refrigerant and R-134a refrigerant must never be mixed, even in the smallest of amounts, as they are incompatible with each other. If the refrigerants are mixed, compressor failure is likely to occur. Refer to the manufacturer instructions included with the service equipment before servicing.
I will leave it up to you as to how you perform this step but know in advance that it is illegal to just discharge this stuff into the air. There, I've done my part for the environment.
Step 2. Remove the battery.
Pretty straight forward step. If you cannot figure out how to do this, you need to stop here and take your car in to be serviced!
Step 3: Remove the battery heat shield.
a) Remove the push-in retainer attaching the air inlet screen and battery heat shield to the plenum panel.
b) Remove the push-in retainer attaching the battery heat shield to the wheelhouse panel.
c) Lift the battery heat shield from the ground stud and remove the shield. There is no nut on the ground stud that holds the battery heat shield in the car.
Step 4. Remove the nut retaining the heater pipe bracket to the cowl.
Step 5. Reposition the heater pipe bracket to access the refrigerant lines.
Step 6. Remove the compressor hose to accumulator retaining bolt.
Cap or tape the open compressor hose and the accumulator immediately to prevent contamination.
Step 7. Disconnect the compressor hose from the accumulator.
Step 8. Discard the O-ring.
Step 9. Reposition the compressor hose end.
That's fancy talk for "move the compressor hose out of your way."
Step 10. Remove the accumulator bracket mounting nuts.
Prior to removal, take note of the accumulator alignment to the accumulator hose and the rear evaporator tube.
Step 11. Reposition the accumulator slightly to access the accumulator hose to accumulator fitting.
You're going to pull the accumulator out a bit so that you can disconnect the remaining hose.
Step 12. Using a back-up wrench on the accumulator fitting (2), loosen the accumulator hose fitting (1) from the accumulator.
If you have a open end wrench that is big enough to turn that gold nut, then you must have one hell of a tool collection. I ended up using a big ol' adjustable crescent wrench to loosen that nut up. However, I will post a picture to show how the service manual states that it should be done.
The service manual says to do it this way. Good luck:
Step 13. Disconnect the accumulator hose from the accumulator.
Step 14. Discard the O-ring.
Step 15. Remove the accumulator from the vehicle.
Step 16. Loosen the accumulator bracket clamp bolt.
One thing you need to do BEFORE you remove the accumulator from the bracket is mark the position of the bracket on the old accumulator. When you go to place the bracket on the new accumulator, you will use these markings to correctly position the bracket in place so that you will not have issues reconnecting the AC lines.
Step 17. Remove the accumulator from the accumulator bracket.
Step 18. Inspect the accumulator bracket insulator and the accumulator lower insulator for wear or damage.
The accumulator lower insulator is the foam piece that is glued to the bottom of the old accumulator. Carefully remove it and glue it to the new accumulator. It is probably not available t the dealership anymore.
Step 19. If replacing the accumulator, drain and measure as much of the oil as possible from the removed accumulator. This measurement will be used during installation of the replacement accumulator.
Step 20. Add 60 ml (2 oz) more than amount drained from old accumulator.
Now at this point, you're ready reassemble everything. Before you do that, you need to replace the orifice. The orifice is located inside the first hose that you disconnected from the accumulator. It looks like a plus sign inside the hose.
As you can see, mine was in really good shape.
That's pretty much it. Put everything back together. The next thing you need to do is go have the system recharged at a qualified service center.
The amount of oil and R-134a is critical to the operation of you AC system. The amounts that you will use of each chemical may vary from what my year requires (2001). Thus, you need to make sure that the amounts needed for your car are exactly to spec. R-134a is NOT like the old freon system where you could just add some until your air ran cold. R-134a amounts must be exact as too much or too little can cause damage as well as cause your AC to not operate correctly. This is why it is so important to have your system filled by a professional who can measure exactly how much substance is in your system.
Heed that warning!!!